Should I Pay Off Debt or Invest? This calculator will help determine whether you should invest funds or pay down debt. You are viewing this website at a small screen resolution which doesn't support calculators. Click here to view this calculator. Have A Question About This Topic? Name Email Address Message Thank you! Oops! Related Content Interested in a Fuel Efficient Car? Estimate how many months it may take to recover the out-of-pocket costs when buying a more efficient vehicle. Federal Income Tax Use this calculator to estimate your income tax liability along with average and marginal tax rates. Put It in a Letter A letter of instruction provides additional and more personal information regarding your estate.